The outcome of outpatient methadone withdrawal reported in 20 published studies during the 1970s varied widely: none to 62% of the patients completed withdrawal, none to 35% became abstinent at termination of withdrawal, and none to 38% were abstinent at follow-up. Although somewhat ambiguous, the results indicated that outpatient withdrawal did not lead to prolonged abstinence in most heroin users. In two studies in San Antonio we attempted to compare opioid use and other behavior during 1 year before and 1 year after outpatient withdrawal. In the first study the before and after comparison of opioid use was unsatisfactory because of follow-up attrition. The frequency of arrest, based on police records and not affected by the follow-up attrition, changed only slightly. In the second study the follow-up attrition was small (8%), and satisfactory comparison could be made. Months abstinent did not increase, but months maintained on methadone increased significantly. The follow-up results did not differ notably from those in inpatient withdrawal. Outpatient withdrawal limited to 21 days has the disadvantage that many persons are prematurely withdrawn and consequently resume heroin use.